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RE: Self-descriptive assertions

From: Williams, Stuart <skw@hp.com>
Date: Thu, 25 Mar 2004 16:59:35 -0000
Message-ID: <E864E95CB35C1C46B72FEA0626A2E80801EA19D6@0-mail-br1.hpl.hp.com>
To: Mark Baker <distobj@acm.org>, Bijan Parsia <bparsia@isr.umd.edu>
Cc: public-sw-meaning@w3.org

Hello Mark,

> Fair enough.  What I meant to say was that from a message 
> sender POV, describing their RDF/XML document as text/plain 
> is one way to avoid communicating the graph.  If any 
> recipient does extract the graph, then that's "sniffing", and 
> "bad" per the TAG finding on authoritative metadata[1].

Hmmm... that's not quite what the finding says... last para section 3.2 [2]

"The Internet media type asserts "this is X", not "process this as follows."
Representation metadata does not constrain the receiving agent to process
the representation data in one particular way."

"this is X" meaning this is an instance of media-type X.

Regards

Stuart
--
[2] http://www.w3.org/2001/tag/doc/mime-respect.html#metadata-sources

> -----Original Message-----
> From: public-sw-meaning-request@w3.org 
> [mailto:public-sw-meaning-request@w3.org] On Behalf Of Mark Baker
> Sent: 25 March 2004 15:56
> To: Bijan Parsia
> Cc: public-sw-meaning@w3.org
> Subject: Re: Self-descriptive assertions
> 
> 
> On Thu, Mar 25, 2004 at 12:56:09AM -0500, Bijan Parsia wrote:
> > >I'm wondering if I had the wrong idea about what folks meant by 
> > >"assert".  I was assuming that in order to have the equivalent of a 
> > >text/calendar document, you'd need the graph plus a statement that 
> > >the graph was asserted.  But what I hear you and Dan saying is that 
> > >the equivalent is just the graph,
> > 
> > So I would assert.
> 
> 8-)
> 
> I should have said before that this resolves my issue with 
> the media type.  Now I'm just trying to understand how all 
> these concepts we've mentioned fit together, if you don't 
> mind helping me out with that.
> 
> > >This would mean that reification, parseType="literal", and using
> > 
> > Reification and literals prevent assertions from the point of view of 
> > the graph
> 
> Right.
> 
> > >text/plain or application/xml, are all mechanisms thatavoid making 
> > >mark:assertions simply by not yielding triples from some RDF/XML.
> > 
> > Where is it mandated that a consumer of application/rdf+xml parses it 
> > to triples?
> 
> Fair enough.  What I meant to say was that from a message 
> sender POV, describing their RDF/XML document as text/plain 
> is one way to avoid communicating the graph.  If any 
> recipient does extract the graph, then that's "sniffing", and 
> "bad" per the TAG finding on authoritative metadata[1].
> 
> > I don't see that that is mandated by anything. It's application 
> > specific. Internet explorer or mozilla rendering using 
> their XML view 
> > can be doing a right thing. A Relax ng validator that checks 
> > application/rdf+xml documents against the relax-ng schema 
> will never 
> > parse to triples but is perfectly ok.
> 
> But a consumer of application/rdf+xml must be able to extract 
> the graph, otherwise they're lying if they say they accept 
> that media type.
> If they only do schema validation, they should advertise that 
> they accept application/xml.  They are still free to validate 
> any */*+xml that they receive, but the important part is that 
> they're not committing to being something that they aren't.
> 
> I believe my position to be consistent with [1], although it 
> goes beyond the scope of that finding.
> 
> > I feel pretty darn Q.E.D.y at this moment. I see no 
> evidence anywhere 
> > in any draft of the registration that suggests anything 
> like what I've 
> > read you to suggest. And I find the counterexamples legion and 
> > compelling. *Even if* anyone found it important to try to specify, 
> > right now, formal technical mechanism for connectng, oh, web 
> > retrievals with assertings of RDF documents (or their graphs), the 
> > media type just is *such* the wrong place to do it.
> 
> As I mentioned above, I'm content that my issue is a 
> non-issue, and I thank everyone for helping me understand this.
> 
>  [1] http://www.w3.org/2001/tag/doc/mime-respect.html
> 
> Mark.
> -- 
> Mark Baker.   Ottawa, Ontario, CANADA.        http://www.markbaker.ca
> 
Received on Thursday, 25 March 2004 12:00:29 GMT

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